This study aims to separate the soil and corm while harvesting water chestnuts on dry land. A spring roller device of soil-corm separation was also designed for the water chestnut harvester, in order to reduce the injury rate of water chestnut. Positive and negative rotating springs were arranged side by side. During the operation of the harvester, the soil-corm mixture was dug out and passed through the lifting device and rubber-roller soil removal device, and then fell into the spring roller soil-corm separation device, where the water chestnuts were further separated from the soil under the vibration and rubbing of the rotating positive and negative spiral spring rollers. The kinetic analysis was performed on the relative motion of the water chestnut and spring roller. The influencing factors on the separation performance were determined as the spring outer diameter, pitch, adjacent spring spacing, height difference and spring speed, line diameter and operation speed. The simulation of soil-corm separation was carried out to optimize the operating performance of the spring roller. The model was then established using EDEM software, including three particles: large soil clods, water chestnuts and fine-grained soil. A single-factor test was carried out on the structural and working parameters of the spring roller, in order to clarify the influence of each factor on the soil-corm separation. Taking the sieving rates of water chestnut and soil as the test indexes, the quadratic regression orthogonal test was also carried out. An optimal combination of parameters was obtained for the spring roller, where the outer diameter was 100 mm, the pitch was 30 mm, the spacing was 9 mm, and the rotational speed was 420 r/min. The better performance was achieved, where the sieving rates of water chestnut and soil were 80%, and 80.69%, respectively. The verification tests were then conducted to compare the prediction of the model. The average relative errors of water chestnut and soil sieving rate were 2.09%, and 2.42%, respectively. The simulated harvesting and one-way tests were carried out to take the test indexes as the rates of the open, the injured, the peeling, and the digging, with the soil moisture content and spring speed as test factors. Among them, the water chestnuts were pre-buried into the soil layer and then harvested. Three wire diameters of springs of 10, 12, and 14 mm were also selected to evaluate the mud-fruit separating of spring rollers. It was found that the 12 mm wire diameter spring shared both better vibration performance and lower damage rate of water chestnut. Actual harvesting tests were conducted to test the performance of the soil-corm separating device. The performance of the water chestnut harvester was measured as follows: the operating speed was 0.21 m/s, the operating efficiency was 0.19 m²/s, the soil breaking rate was 75.61%, the open water chestnut rate was 82.42%, the injured water chestnut rate was 14.73%, and the peeling water chestnut rate was 7.01%. The soil crushing and soil-corm separation were enhanced with the increase in rotational speed. However, the injury rate of the water chestnut also rose, and the rotational speed of the spring roller should not be more than 244.5 r/min. The broken soil rate was outstandingly improved with the reduction of soil moisture content, but the injured rate of water chestnut increased as well. The damage rate of water chestnut more outstandingly increased with the decrease of soil moisture content at the soil moisture content of 15.77% to 17.44%, compared with the soil moisture content of 17.44% to 19.40%. The finding can provide a strong reference for the development and optimization of water chestnut harvester.

Ratoon rice is a typical cultivation to allow for the growth of another crop of rice using dormant seedlings from the previous harvest. Seedling, raising, and transplanting of double-season rice can be removed to reduce the harm from pesticide residues. Cultivated land quality can also be protected at a low cost. Additionally, the quality and fullness of the second crop of ratoon rice are superior to that of double-season rice. The planting area of machine-harvested ratoon rice has increased rapidly in recent years. Therefore, most research has been focused on the harvest technology and equipment of ratoon rice. Particularly, ratoon rice harvesting is required for the low rolling and high stubble retention for optimal agronomic conditions. The rolling of rice stubble during harvest in the main season can significantly reduce the yield of ratoon rice in the ratoon season. Once the lodging occurs at the mature stage of crop growth, it is detrimental to the harvesting yield and quality. Therefore, the optimal path of harvesting is crucial to improve the efficiency of grain production for better harvesting with minimal loss. Concurrently, the volume limit of the grain bin in the harvesters and the location of the unloading points also exert a significant impact on the loss of harvesting and low rolling of the ratoon rice. Therefore, it is necessary to design the harvest path of the ratoon rice harvesters for the maximum yield in the main season. The optimal path for high-quality agricultural machinery is crucial to saving time and energy, particularly for better operation efficiency and quality with less soil rolling. In this study, a path planning was proposed, called the harvester grain bin capacitated arc routing (HGBCARP). Two modules consisted of information processing and path planning. The information processing module was used to convert the operation information (such as farmland boundaries, unloading point positions, crop lodging directions, and area positions) into a processable data form, and then transmit it to the path planning module. The optimal path planning was obtained after the tasks, such as the direction division of the operation line, the optimization of the operation line traversal sequence, the generation of turning modes, and the calculation of the rolling area. An improved genetic algorithm was utilized to evaluate the performance of three new types of ratoon rice harvesters, as well as two traditional rice harvesters. Three parameters of the field test were taken as evaluation indicators, including the length of the driving path, the rolling area, and the amount of harvested grain. A comparative simulation was then conducted under three field conditions using rotary and HGBCARP harvesting path planning. It was found that the rolling area of the HGBCARP harvesting path was 11.79% to 27.20% less than that of the rotary type. The rolling area was reduced to increase the yield of the main season rice by 1.64% to 1.95%. Additionally, the HGBCARP harvesting path was found to reduce the rolling area by 7.25% to 20.09%, compared with the rotary type. Field harvesting experiments were carried out using an electric unmanned crawler chassis on various harvesting paths. The HGBCARP harvesting path was found to reduce the rolling area by 11.21% to 28.03% and the path length by 6.81% to 23.46%, compared with the traditional cattle tillage reciprocating and rotary harvesting paths. The high effectiveness was achieved in the HGBCARP path planning. This finding can also provide a valuable reference for intelligent operation path planning.